Apparatus for aerating liquids



April 26, 1938. J. F. ATKINSON ET AL APPARATUS FOR AERATING LIQUIDSFiled April 2 1954 Patented Apr. 26, 1938 APPARATUS FOR AERATING LIQUIDSJohn F. Atkinson and Cleo E. Brown, Harrisonville;

0., assignors, by mesne assignments, to

International Filter 00., a corporation of Delaware Application April 2,1934, Serial No. 718,595

to provide such an apparatus whereby large quan-.

tities of liquid may be treated in an apparatus that is simple andcompact, occupying little space. Another object. is to provide for suchtreatment in an apparatus that may be totally enclosed whereby splashingis overcome and also interference by a surrounding atmosphere avoided.Another object is to prolong the period of treatment by the provision ofretention pools wherein the liquid is held following exposure to thegas. Another object is to provide such an apparatus wherein the liquidis repeatedly and alternately brought together in a body and separatedas a spray or sheet, whereby most thorough and complete treatment may bereceived. An- 20 other purpose is to improve such treatment by providinga process wherein contact and interaction between the liquid and' gas issecured by repeatedly varying the nature of the flow of the liquidduring its passage and to provide an apparatus wherein a variety ofsuitable forms of flow are secured.

Other objects will become apparent from consideration of the followingdisclosure. It will be apparent also that instead of being looked atfrom the aspect of liquid treatment it may be regarded also as providingan excellent means for the treatment of a gas.

Since the most common such liquid treatment and that carried out on themost extensive scale is the aeration of water, our invention will bedescribed in connection therewith and from this description its utilityand how it may be employed for other treatments will be apparent.

40 A great variety of. methods and equipment have hitherto been used forthe aeration of Water. In some cases the water is sprayed out into theair through a nozzle under pressure and allowed to fall back into a pan.This is an effec- 45 tive method but requires much area as the water isusually projected several feet vertically and horizontally. Thus acommon type of' nozzle throwing 150 gallons per minute will cover anarea about 15 feet in diameter. In another 50 method the water istrickled down over pieces of coke, stone, or other hard substance heldin a frame or tray. In the best construction, the coke or other materialis divided into several shallow beds spaced apart Vertically so that thewater v 55 will drip from one tray to the next, as well as trickle overthe coke. With a proper number, depth and spacing of trays, the flow maybe of the order of gallons per sq. ft. per minute. A third method is toflow the water over a series of vertically spaced trays. Usually theseare circular with a smaller diameter tray at the top, the diameterincreasing downward. With such construction the bottom tray may be about5 feet in diameter for a capacity of 150 gallons per minute. These arethe accepted and commonly used forms or methods, there beingconsiderable variation in 10 details of construction and arrangement.Occasionally some mechanical means such as compressed air or paddles isused but these cost more for operation and are only adopted when somespecial condition is to be met, such as lack of head. The simplicity andsmall space required by our improved method and apparatus and otheradvantages thereof as compared with means such as those referred to willbe apparent from what follows, it being noted that we havesatisfactorily number of plants, large and small, employing this 26process, either alone or in connection with some other treatment. Theimprovement sought in a water may be any one or more of several kindsand may result from'either a mechanical or a chemical effect had byaeration, or both. Thus 30 the removal of dissolved carbon dioxide fromwater by aeration is probably purely mechanical while the changing offerrous iron to ferric form to cause or aid precipitation thereof is, sofar as such action is concerned, purely chemical. Aeration of Water iswidely used to overcome objectionable tastes or odors and in such casesthe effect may be the result of either chemical or physical action, orboth, depending upon the particular impurity or impurities present. Insuch cases there may be oxidation or mechanical separation, or both.

In some cases the amount of air required to treat a given volume ofwater may be very small indeed, as for instance to raise ferrous iron toferric form. The amount of iron present in water is very small, usuallyonly a few parts per million, and the amount of oxygen requiredproportionately small. Usually there is no objection to applying muchmore air than is needed to supply the required oxygen and it may bedesirable to do so for other purposes; however where excess oxygen is tobe avoided or .where our method is used for some other treatment, ourenclosed apparatus treatment of a large volume of liquid with a smallvolume of gas or when the treatment requires very intimate and prolongedcontact. These arise out of the characteristics of our method andapparatus wherein the gas is first thoroughly mingled with or beateninto the liquid, the two then being wholly or partially separated, theseactions being repeated as often as is considered necessary, whileperiodically the water passes through what serve as retention chambersto delay its passage so that reaction time is provided for, and in asimilar manner the gas is held so as to be fully utilized.

In the accompanying drawing, Fig. 1 is a ver- I tical sectional viewofone form of. ourapparatus.

- bers of what may be'a series of inverted, truncated cones or funnelsmounted within the cylinder I and preferably sealed thereto around theirupper edges. Below the open ends of cones 2 are positioned the smallercones 4, the upper edges of which. are spaced above the lower edges ofcones 2, as hereinafter referred .to. In Fig. 1, the cones 4 are shownmounted on the central riser pipe 3 and adjustable thereon by means ofset screws 5 and ordinarily they should fit the pipe loosely or a drainhole may be provided so that they will empty when treating flow ceases.The rods 1, extending from the base 8 through lugs 6 support cylinder land with it the cones 2, and by means of the nuts 9 these parts may beraised and lowered to space the lower ends of cones 2 from cones 4 asrequired. Spacers ID are shown by means of which the lower ends of cones2 are held concentric with pipe 3 but these are'not an essential part ofthe apparatus.

In operation water flows through pipe 3 and in the form shown in Figs. 1and 2 overflows at the face exposure to air but also a considerableamount of air becomes mingled with the water in the form of smallbubbles. As this rushing flow of water down thesteep sides of the conestrikes the surface of the pool of retained water, it .entrains stillmore air and because of the considerable energy in the rapidly flowingwater, sets up a very violent agitation or turbulence in the pool sothat the bubbles of air are carried through the volume thereof andmostly retained so as to be carried down through the orificeopeningwardly, striking the wall of cylinder l or that of the next cone 2according to the volume of flow.

In the second cone the actions as above described are repeated butnormally the water isprojected upwardly and outwardly with considerablymore velocity and energy from cone 4 than from the top of entry pipe 3and consequently there is a greater spraying and spattering action inthe second and subsequent chambers, or if there be but one cone then thespraying into the air oc-. ours on discharge therefrom.

It will be apparent that during the passage of the water through thepath referred to it is continually in contact with the air, and alsothat this contactis had in several different ways( Thus the water isfirst sprayed through the air, then it flows down the walls of the cone,there is the turbulent body of mixed'water and air in the lower end ofthecone and from here it is finally sprayed out again. These variationsin condidirectly in the sense of changing the kind of .re-

action had but because of the repeated breaking 7 Furthermore time forreaction is provided by the retention period and this under conditionssuch that more'oxygen is at hand for absorption if needed; If the resultsought be not oxidation as just spoken of but a mechanical effect suchas removal of a dissolved gas,'the facilities provided are equallygood.In such a case the result obtained is ultimately dependent upon partialva-.

por or gas pressures, but the degree of contact and thoroughness ofmingling of the water and ;While the number of cones may be so varied,we

have so far not found any appreciable benefit by using more than three.Thus in treating a water taken from a small lake that had abundant algaegrowth, the water having pronounced and objectionable taste and odor, wefound improvement using up to three cones but not beyond that number andour observations lead us to believe that in the great majority of casesthis is the optimum number. portions of the cones have some importance,probably fromsome effect on the kind or degree of mixing or agitationobtained and the amount of air entrained and carried along. While wetried cones of various angles and a certain range is permissible, ourbest resultswere had when the walls of the large cones 2 were at anangle of about 10 from the vertical, that is, when the included anglewas about 20.

The size of the cones will of course depend upon the quantity of liquidto be treated and only general information can be given. The diameter ofconduit 3 will be chosen according to the flow and the top of it shouldbe at or a little above the level of the top of the upper cone. Thediameter of the cone 2 at the top should be such that the watermushrooming out from the pipe will strikeit near the top at the maximumrated flow. The annular space or orifice between the pipe and the coneat the bottom thereof should be such that We found also that the form orpro-r 20 tions of flow may not affect the chemical reactions of Fig. 1.

at the maximum water flow the cone will not become more than about halffull. The angle and other proportions of the cones 4 are not soimportant, although we have used satisfactorily an included angle ofabout 30. They should be spaced upon this pipe 3 so that each will bevertically in the same relation to its cone 2. These cones 4 serve. adouble purpose. They not only spray the water upward and outwardly aspreviously referred to, but also when the part I carrying the cones 2 israised or lowered by means of the nuts 9, they may serve to vary therestriction at the bottom of the cones 2 and so to adjust for varyingflows of water. The top of cones 4 should not extend too far above thebottom of cones 2 or too much liquid may be held back in 2 and alsoproper spraying efiect may not be secured. While great exactness here isnot required, yet at the normal rated flow the distance from the bottomof a cone 2 to the top edge of its associated cone 4 may well .be of theorder of about one inch. In general, flows over the range of 2-1 may betaken care of without such vertical adjustment of cones 2 but additionalrestriction is usually desirable at lower flows. This is partly tosecure proper spraying out but also to secure proper retention in thecone 2. While for the reasons given and others that are apparentcomplete specific data cannot be given, yet it may be said that theapparatus shown in Fig. 1 is quite closely to scale for an apparatus nowin use handling from 200 to 400 gallons per minute, the diameter of thecones 2 at the top being in this case 24 inches and the diameter of pipe3 being 6 inches.

In Fig. 2 the cone 2 is provided with a straight section or skirt l2 atthe bottom and instead of the cones 4 of Fig. 1 a flat plate I3 isindicated. These forms may he sometimes used either singly or incombination, as where conditions are otherwise favorable to ease oftreatment, but they have not been found as satisfactory as the form Thepart l2 by providing a downdraft or so-called negative head effectsecures a greater flow without causing too deep a pool or so large avolume to be held in 2.

In Fig. 3 is shown another modification that may be used when the supplyis from above. In this form the pipe 3 discharges onto plat-e M. Thedischarge from 2 is through a circular orifice instead of an annularorifice at the bottom thereof, into cone 4. Cone 4 is provided with adrain hole 15 and may be supported by straps not shown from cones 2, orfrom enclosure I if adjustment is not required. Where adjustment isdesirable, a central rod or column extending from the floor or fromplate l4 corresponding to pipe 3 of Fig. 1, will carry parts 4. Themanner of securing such support will be readily understood withoutfurther explanation.

Very considerable quantities of air are carried through the apparatuswith or by the water so that ample opportunity for aerating efiect isprovided. In general we prefer that part I form a tight enclosure and wehave so 'far for some reason had the best results with that coflstruction, but we do not doubt that in some cases this will not provenecessary. If only a limited quantity of air or other gas is to be drawnthrough, a cover 18 having the inlet l1 containing the adjustment "5 maybe provided, as indicated in Fig. 2.

It will be apparent from the preceding description taken with thedrawing, that our invention provides a novel and useful method oftreating also that we have provided a very simple and compact apparatuswhereby our improved treatment may be carried out and the objects soughtsecured.

We claim:

1. In apparatus of the character described, the combination of a watersupply pipe, a series of vertically spaced hydraulic head providing andwater retaining basins each of which has a submerged discharge openingin the lower portion thereof, said openings being so restricted in areaas to cause water to be retained in said basins to build up a headtherein over said openings, and means that include a basin wall wherebythe water is caused to flow radially outward and then radially inwardduring passage from the discharge opening of an upper basin to that ofthe next lower basin.

2. Apparatus of the character described comprising a vertically disposedfluid inlet pipe, a plurality of relatively large vertically spacedliquid retaining basins each having a submerged liquid discharge openingin the lower part thereof, said openings being of such restricted areaas will at normal flow retain a substantial depth of liquid in saidbasin, and a relatively small flow guiding and directing memberintermediate upper and lower discharge openings, said member beingclosed at the bottom, said basins and said members being symmetricallydisposed circumferentially of said pipe.

3. In apparatus of the class described, the combination of a watersupply pipe, a series of vertically spaced hydraulic head providingbasins each having a submerged discharge opening in the lower portionthereof, the upper of said basins being so placed as to receive thedischarge from said pipe, a substantially smaller and shallowerintermediate basin below each of said discharge openings to receivedischarge therefrom, said intermediate basins being closed at the lowerportion and so shaped at the sides as to direct upwardly the flowingwater.

4. In apparatus of the character described, the combination of a liquidinlet pipe and a series of regularly vertically spaced, alternatelylarger and smaller basin members mounted below the discharge end of saidinlet, said larger members being of substantial liquid holding depth toserve as liquid retention basins and being provided in their lower partwith a submerged discharge opening of such restricted area as to requirea head thereover equal to at least about one half the basin depth toeffect normal flow discharge therethrough, there being a smaller memberunder each such opening to receive the discharge therethrough, s'aidsmaller members being closed at their lower portion and discharging overtheir upper edges.

5. In apparatus of the character described, a vertical cylindricalenclosing member, a plurality of inverted truncatedconical membersmounted concentrically therein and attached thereto, an inlet conduitconcentric therewith and having its discharge end adjacent the upperpart of the upper cone, and a plurality of inverted truncated conicalmembers mounted on said conduit, each in such vertical spacedrelationship with one of the first named conical members as to restrictdischarge therefrom.

said enclosing ring in position such that the lower end of the inwardlyand downwardly flaring ring is within and below the upper edge of thefirst named ring. v

8. The apparatus of claim 7 wherein the mounting means is provided withadjusting means for varying the vertical spacing of said inwardly andoutwardly flaring rings.

JOHN F. ATKINSON. CLEO E. BROWN.

